PublicationNewspaper Article EU must not burn the world’s forests for ‘renewable’ energy

December 14, 2017
  • Kammen, Daniel
  • J. Beddington
  • S. Berry
  • K. Caldeira
  • W. Cramer
  • F. Creutzig
  • E. Lambin
  • S. Levin
  • W. Lucht
  • G. Mace
  • W. Moomaw
  • P. Raven
  • T. Searchinger
  • N. C. Stenseth
  • J. P. van Ypersele
Publication Type:
Newspaper Article

A flaw in Europe’s clean energy plan allows fuel from felled trees to qual­ify as renew­able energy when in fact this would accel­er­ate cli­mate change and dev­as­tate forests


The Euro­pean Union is mov­ing to enact a direc­tive to dou­ble Europe’s cur­rent renew­able energy by 2030. This is admirable, but a crit­i­cal flaw in the present ver­sion would accel­er­ate cli­mate change, allow­ing coun­tries, power plants and fac­to­ries to claim that cut­ting down trees and burn­ing them for energy fully qual­i­fies as renew­able energy.

Even a small part of Europe’s energy requires a large quan­tity of trees and to avoid pro­found harm to the cli­mate and forests world­wide the Euro­pean coun­cil and par­lia­ment must fix this flaw.

Euro­pean pro­duc­ers of wood prod­ucts have for decades gen­er­ated elec­tric­ity and heat as ben­e­fi­cial by-​​products, using wood wastes and lim­ited for­est residues. Most of this mate­r­ial would decom­pose and release car­bon diox­ide in a few years any­way, so using them to dis­place fos­sil fuels can reduce the car­bon diox­ide added to the atmos­phere in a few years too.


Unfor­tu­nately, the direc­tive mov­ing through par­lia­ment would go beyond wastes and residues and credit coun­tries and com­pa­nies for cut­ting down addi­tional trees sim­ply to burn them for energy. To do so has fun­da­men­tally dif­fer­ent con­se­quences because the car­bon released into the air would oth­er­wise stay locked up in forests.

The rea­son­ing seems to be that so long as forests re-​​grow, they will even­tu­ally reab­sorb the car­bon released. Yet even then, the net effect – as many stud­ies have shown – will typ­i­cally be to increase global warm­ing for decades to cen­turies, even when wood replaces coal, oil or nat­ural gas.


The rea­sons begin with the inher­ent inef­fi­cien­cies in har­vest­ing wood. Typ­i­cally, around one third or more of each tree is con­tained in roots and small branches that are prop­erly left in the for­est to pro­tect soils, and most of which decom­pose, emit­ting car­bon. The wood that is burned releases even more car­bon than coal per unit of energy gen­er­ated, and burns at a lower tem­per­a­ture, pro­duc­ing less elec­tric­ity – turn­ing wood into com­pressed pel­lets increases effi­ciency but uses energy and cre­ates large addi­tional emissions.

A power plant burn­ing wood chips will typ­i­cally emit one and a half times the car­bon diox­ide of a plant burn­ing coal and at least three times the car­bon diox­ide emit­ted by a power plant burn­ing nat­ural gas.


Although regrow­ing trees absorb car­bon, trees grow slowly, and for some years a regrow­ing for­est absorbs less car­bon than if the for­est were left unharvested.

Even­tu­ally, the new for­est grows faster and the car­bon it absorbs, plus the reduc­tion in fos­sil fuels, can pay back the “car­bon debt”, but that takes decades to cen­turies, depend­ing on the for­est type and use. We con­ser­v­a­tively esti­mate that using delib­er­ately har­vested wood instead of fos­sil fuels will release at least twice as much car­bon diox­ide to the air by 2050 per kilo­watt hour. Doing so turns a poten­tial reduc­tion in emis­sions from solar or wind into a large increase.

Time mat­ters. Plac­ing an addi­tional car­bon load in the atmos­phere for decades means per­ma­nent dam­age due to more rapid melt­ing of per­mafrost and glac­i­ers, and more pack­ing of heat and acid­ity into the world’s oceans. At a crit­i­cal moment when coun­tries need to be “buy­ing time” against cli­mate change, this approach amounts to sell­ing the world’s lim­ited time to com­bat cli­mate change under mis­taken claims of improvement.


The effect on the world’s forests, car­bon and bio­di­ver­sity is likely to be large because even though Europe is a large pro­ducer of wood, its har­vest could only sup­ply about 6% of its pri­mary energy. For more than a decade, the increased use of bio­mass has been sup­ply­ing roughly half of Europe’s increase in renew­able energy. To sup­ply even one third of the addi­tional renew­able energy likely required by 2030, Europe would need to burn an amount of wood greater than its total har­vest today. This would turn a likely 6% decrease in energy emis­sions by 2050 under the direc­tive through solar and wind into at least a 6% increase.

Europe’s own demand for wood would degrade forests around the world, but if other coun­tries fol­low Europe’s exam­ple, the impacts would be even more dan­ger­ous. Instead of encour­ag­ing Indone­sia and Brazil to pre­serve their trop­i­cal forests – Europe’s present posi­tion – the mes­sage of this direc­tive is “cut your forests so long as some­one burns them for energy”. Once coun­tries are invested in such efforts, fix­ing the error may become impos­si­ble. To sup­ply just an addi­tional 3% of global energy with wood, the world needs to dou­ble its com­mer­cial wood har­vests at great costs to car­bon and wildlife.


Nei­ther a require­ment that forests be man­aged sus­tain­ably nor any other “safe­guards” in the var­i­ous work­ing drafts would stop this. For exam­ple, the direc­tive would ban wood if har­vests under­mined “the long-​​term pro­duc­tiv­ity capac­ity of the for­est”. Although that sounds good, pre­serv­ing the capac­ity of trees to grow back still leaves more car­bon in the air for at least decades. Restrict­ing wood har­vests to coun­tries with net grow­ing forests – another idea – would still take car­bon that forests would oth­er­wise add to their stor­age and instead put it in the air with­out mean­ing­ful global limits.


The solu­tion is to restrict eli­gi­ble for­est bio­mass to its tra­di­tional sources of residues and waste. Leg­is­la­tors will likely be able to vote on such an amend­ment in the parliament’s plenary.

By 1850, the use of wood for bioen­ergy helped drive the near defor­esta­tion of west­ern Europe even at a time when Euro­peans con­sumed rel­a­tively lit­tle energy. Although coal helped to save the forests of Europe, the solu­tion is not to go back to burn­ing forests. As sci­en­tists, we col­lec­tively have played key roles in the IPCC, in advis­ing Euro­pean gov­ern­ments, and in for­est and cli­mate research. We encour­age Euro­pean leg­is­la­tors and other pol­i­cy­mak­ers to amend the present direc­tive because the fate of much of the world’s forests is lit­er­ally at stake.


Prof John Bed­ding­ton, Oxford Mar­tin School, for­mer chief sci­en­tist to the UK gov­ern­ment; Prof Steven Berry, Yale Uni­ver­sity; Prof Ken Caldeira*, Stan­ford Uni­ver­sity and Carnegie Insti­tu­tion for Sci­ence; Wolf­gang Cramer*, research direc­tor (CNRS), Mediter­ranean Insti­tute of marine and ter­res­trial bio­di­ver­sity and ecol­ogy; Felix Creutzig*, chair Sus­tain­abil­ity Eco­nom­ics of Human Set­tle­ment at Berlin Tech­ni­cal Uni­ver­sity and leader at the Mer­ca­tor Research Insti­tute on Global Com­mons and Cli­mate Change; Prof Dan Kam­men*, Uni­ver­sity of Cal­i­for­nia at Berke­ley, direc­tor Renew­able and Appro­pri­ate Energy Lab­o­ra­tory; Prof Eric Lam­bin, Uni­ver­sité catholique de Lou­vain and Stan­ford Uni­ver­sity; Prof Simon Levin, Prince­ton Uni­ver­sity, recip­i­ent US National Medal of Sci­ence; Prof Wolf­gang Lucht*, Hum­boldt Uni­ver­sity and co-​​chair of Pots­dam Insti­tute for Cli­mate Research; Prof Georgina Mace FRS*, Uni­ver­sity Col­lege Lon­don; Prof William Moomaw*, Tufts Uni­ver­sity; Prof Peter Raven, direc­tor emer­i­tus Mis­souri Botan­i­cal Soci­ety, recip­i­ent US National Medal of Sci­ence; Tim Searchinger, research scholar, Prince­ton Uni­ver­sity and senior fel­low, World Resources Insti­tute; Prof Nils Chris­t­ian Stenseth, Uni­ver­sity of Oslo, past pres­i­dent of the Nor­we­gian Acad­emy of Sci­ence and Let­ters; Prof Jean Pas­cal van Yper­sele, Uni­ver­sité Catholique de Lou­vain, for­mer IPCC vice-​​chair (2008–2015).


Those marked * have been lead authors on IPCC reports.


For more on Pro­fes­sor Kam­men and the Renew­able and Appro­pri­ate Energy Lab­o­ra­tory’s work on bio­mass, click here and search ‘biomass’

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